Java tutorial
//Copyright 2007-2009 David Yu dyuproject@gmail.com //------------------------------------------------------------------------ //Licensed under the Apache License, Version 2.0 (the "License"); //you may not use this file except in compliance with the License. //You may obtain a copy of the License at //http://www.apache.org/licenses/LICENSE-2.0 //Unless required by applicable law or agreed to in writing, software //distributed under the License is distributed on an "AS IS" BASIS, //WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. //See the License for the specific language governing permissions and //limitations under the License. //package com.dyuproject.util; import java.lang.reflect.Array; /** * @author David Yu * @created Jan 16, 2009 */ public final class ArrayUtil { /** * Copies the elements of the {@code oldArray} to a new array with extra space to * append the given element {@code toAppend}. */ @SuppressWarnings("unchecked") public static <T> T[] append(T[] oldArray, T toAppend) { Class<?> component = oldArray.getClass().getComponentType(); T[] array = (T[]) Array.newInstance(component, oldArray.length + 1); System.arraycopy(oldArray, 0, array, 0, oldArray.length); array[oldArray.length] = toAppend; return array; } /** * Copies the elements of the {@code oldArray} to a new array with extra space to * append the given element {@code toAppend1} and the array {@code toAppend2}. */ @SuppressWarnings("unchecked") public static <T> T[] append(T[] oldArray, T toAppend1, T[] toAppend2) { Class<?> component = oldArray.getClass().getComponentType(); T[] array = (T[]) Array.newInstance(component, oldArray.length + 1 + toAppend2.length); System.arraycopy(oldArray, 0, array, 0, oldArray.length); array[oldArray.length] = toAppend1; System.arraycopy(toAppend2, 0, array, oldArray.length + 1, toAppend2.length); return array; } /** * Copies the elements of the {@code oldArray} to a new array with extra space to * append the given array {@code toAppend}. */ @SuppressWarnings("unchecked") public static <T> T[] append(T[] oldArray, T[] toAppend) { Class<?> component = oldArray.getClass().getComponentType(); T[] array = (T[]) Array.newInstance(component, oldArray.length + toAppend.length); System.arraycopy(oldArray, 0, array, 0, oldArray.length); System.arraycopy(toAppend, 0, array, oldArray.length, toAppend.length); return array; } /** * Copies the elements of the {@code oldArray} to a new array with extra space to * append the given array {@code toAppend1} and the element {@code toAppend2}. */ @SuppressWarnings("unchecked") public static <T> T[] append(T[] oldArray, T[] toAppend1, T toAppend2) { Class<?> component = oldArray.getClass().getComponentType(); T[] array = (T[]) Array.newInstance(component, oldArray.length + toAppend1.length + 1); System.arraycopy(oldArray, 0, array, 0, oldArray.length); System.arraycopy(toAppend1, 0, array, oldArray.length, toAppend1.length); array[array.length - 1] = toAppend2; return array; } /** * Copies the elements of the {@code oldArray} to a new array with extra space to * append the given array {@code toAppend1} and the array {@code toAppend2}. */ @SuppressWarnings("unchecked") public static <T> T[] append(T[] oldArray, T[] toAppend1, T[] toAppend2) { Class<?> component = oldArray.getClass().getComponentType(); T[] array = (T[]) Array.newInstance(component, oldArray.length + toAppend1.length + toAppend2.length); System.arraycopy(oldArray, 0, array, 0, oldArray.length); System.arraycopy(toAppend1, 0, array, oldArray.length, toAppend1.length); System.arraycopy(toAppend2, 0, array, oldArray.length + toAppend1.length, toAppend2.length); return array; } /** * Returns a copy of the old array {@code oldArray} but with the element at the * give index {@code idx} removed. * * @throws {@link IllegalArgumentException} if the array index is out of bounds. */ @SuppressWarnings("unchecked") public static <T> T[] remove(T[] oldArray, int idx) { if (idx < 0 || idx >= oldArray.length) throw new IllegalArgumentException("array index " + idx + " out of bounds"); Class<?> component = oldArray.getClass().getComponentType(); T[] array = (T[]) Array.newInstance(component, oldArray.length - 1); if (idx == 0) System.arraycopy(oldArray, 1, array, 0, array.length); else { System.arraycopy(oldArray, 0, array, 0, idx); System.arraycopy(oldArray, idx + 1, array, idx, array.length - idx); } return array; } }